Insistent, resolute (7)
I believe the answer is:
adamant
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">insistent</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">resolute</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(both can mean determined)</span><br/ ><br/ ></span>
(Other definitions for adamant that I've seen before include "Determined and unyielding to requests" , "Hard and unrelenting" , "Fabulous rock" , "6a [PRINCESS IDA] 's fortress < for unyielding" , "Legendary rock" .)